Using @#!$? Twitter to Make Money

What's the twitter business model?

Earlier today I wrote about the new Gamejabs service that extends twitter for its followers by making use of the ! instead of the #. At the time I suggested that symbols could be used to categorize tags - kind of a meta-meta-tag. The examples were:

• @ for people or groups (twitter)
  
• # for events (twitter)
  
• ! for sports teams (Gamejabs)
• $ for financial, investment entities
• ? for entertainment - movies, music, television
  

This then turned into a money-making idea for twitter. Instead of the usual advertising or subscriptions, pay for the creation and ownership of a tag. Twitter should and can control its platform, so the value appears to be around what is being discussed and we use hashtags already. A potential model:

• Sign-ups (@) are free.
• Events (#) are free or paid listings by commercial organizations.
• Sports services (!) are subscription with added functionality, a la Gamejabs.
• Companies are definitely paid ($) and return company info - like news, stock quotes, jobs, etc.
• Entertainment (?) are paid by movies, TV, and bands - exclusive content for followers.
  

What other tags can we use?